1. Field of the Invention
The present invention relates to a device for the collection, storage, and transfer of a blood or specimen sample obtained from a patient for medical diagnostic testing. More specifically, the present invention relates to a device for capillary collection of blood samples from a skin surface of the patient. The device includes a collection tube having a lip feature surrounding a top opening of the tube suitable for collecting samples from a skin surface. The device also includes a cap assembly having a stopper for closing and sealing the tube after the blood or specimen sample has been collected. The stopper incorporates space elimination features to funnel the blood or specimen sample to a probe assembly of a testing instrument during transfer from the collection tube.
2. Description of Related Art
Conventional capillary collection devices according to the prior art typically provide a microtube or collection container having a raised receiving lip or funnel feature that engages the skin surface of a patient that has been pierced so as to draw a blood sample from the capillaries located just beneath the skin surface. The internal collection cavities of such prior art collection containers are typically straight-walled and provide no features for promoting the flow of drawn blood into the cavity during collection or the flow of blood to the testing instrument during transfer. Thus a significant amount of the collected blood or specimen sample is caught on the sidewall of the cavity due to surface tension during collection and during transfer.
After collection, these tubes are sealed by a cap assembly disposed on the collection container. Conventional cap assemblies provide a flat bottom surface in communication with the collection cavity. As a result, a significant amount of dead volume of sample is created within the collection cavity during transfer since neither the collection container nor the cap assembly adequately funnel or channel the collected blood sample to the aspiration hole of the probe needle. As can be appreciated, conventional prior art collection devices create a significant amount of wasted sample and require a significantly higher volume of sample to be collected than what is actually needed to perform the diagnostic tests for which the sample is being collected. Sample volumes are particularly important in capillary applications, where a very small volume of blood is typically collected and/or available, and therefore avoiding any waste is particularly important.